1. Field of the Invention
Where objects such as cables, cable trays, conduits, mechanical piping, ducts and the like pass through openings in walls, ceilings or floors of commercial and industrial buildings, it is desired to seal these openings to aid in confining fire, smoke, toxic or corrosive fumes and water damage. The present invention provides a closure for such surface openings having one or more of the above mentioned objects passing therethrough formed by positioning a non-liquid, non-combustible substance in the void of the opening to block or substantially block the void and applying an elastic coating over the substance and the object adjacent its passage through the substance in the opening to accommodate relative movement between the object and the closure without forming cracks in the closure.
2. Description of the Prior Art
Wall openings receiving objects such as cables, cable trays, conduits, mechanical piping, ducts and the like therethrough are referred to as "penetrations" and seals employed in an effort to seal off the void of the opening around the objects are called penetration seals, penetration sealing systems, fire stops or fire barriers. While the penetration seals are normally tested at various recognized testing laboratories in accordance with recognized procedures well known to those skilled in the art, most penetration seals will never be exposed to an active fire, and primary concerns of users are centered around functional performance and maintenance considerations of the seals - that is, maintaining the seal without cracks which most generally are caused by movement of the object relative to the seal through which it passes due to expansion and contraction.
The prior art with which Applicant is familiar is U.S. Pat. No. 3,022,190 and U.S. Pat. No. 3,642,531. However, neither of these patents deal with penetration seals; U.S. Pat. No. 3,642,531 relates to a cable coating, and U.S. Pat. No. 3,022,190 relates to a process and composition for controlling temperatures.
Penetrating fire stops, that is, seals which stop fire, smoke, toxic or corrosive gases and water damage from passing through openings in the floor and wall into other building areas have been available in several types. A so called mechanical type penetrating fire stop is a mechanical seal that must be built into the wall or floor as the building structure is being erected. Generally speaking, such fire stops will hold a specific number and size of cables, but will not accommodate cable trays, large piping or ducts through the mechanical seal. The rigid engineering and construction requirements, high cost per square foot of the mechanical seals and their lack of versatility make them less desirable for most applications outside of the petrochemical industry. On the other hand, the substantial resistance to explosions of such mechanical stops may make them very desirable, even at higher costs in the petrochemical industry.
Non-mechanical type fire stops or penetration fire stops are generally more versatile in their application to structures where the penetration hole sizes and shapes are designed to accommodate cable trays, piping and the like. They are generally less expensive in overall cost and allow cable trays, pipes and ducts to pass through the penetration opening and seal. The non-mechanical type penetration fire stop can be generally classified in two categories, that is, (1) pour in type of fill materials and (2) surface coating types. The pour in type of fill material fire stop is produced by placing temporary or permanent damming material on both sides of a wall opening or on the bottom side of a floor opening and pouring the liquid sealing or fill material into the cavity (penetration opening) between the damming material in walls or on top of the damming material in floor openings. A penetration fire stop, using this type of prior art construction, may be made, for example, by pouring three inches or more of liquid including foam, gypsum, lightweight concrete, intermecent caulk, or fire resistant mastic into the opening to form the seal.
A surface coating type of fire stop is produced by placing permanent, non-liquid insulation material into or over the floor or wall cavity which forms the penetration opening. The permanent non-liquid insulation material is of a non-combustible type, such as mineral wool, silica fiber, alumina silica fiber, Fiberglas or refractory materials. These insulation materials are almost all of the soft to semirigid type, meaning that they will compress slightly to moderately under pressure. Such material is placed in or over the void forming the penetration opening and positioned to fit tightly around the penetration items, that is, around the cable trays, conduits, mechanical pipes, cables and ducts passing through the penetration opening to form an exposed surface or dam over which a sealing, fire resistant and/or fire retardant coating is applied. When this coating dries, it provides an exposed surface to the completed penetration fire stop that is usually water resistant and in many cases is airtight or nearly airtight.
The coatings used with prior art damming material or substances are formed from material so that they have very little or substantially no elongation.
As a result, when the penetrants going through the penetration opening move in any direction, that is, by way of example, parallel to the wall or floor in which the penetration opening is located, the coating over the damming material breaks loose from the penetrants and may also break loose from the damming material over which it is applied. The break or crack normally occurs at the intersection of the penetrant (object going through the seal), and the exposed face of the seal and is caused because the coating over the damming material, or substance, is not elastic and does not stretch to accommodate such movement of the penetrants, whether they be cable, cable trays or other objects, so that movement of the penetrants due to expansion or contraction or due to other causes generally causes cracks in the seal through which smoke, gases, water or fire may pass from one building area to another.